How to configure auto reply for staff?

Staff can do it by themselves.

Administrator can also do it for them. 1. log in 'https://webmail ...' with Administrator account.
2. Click on 'Options'.
3. At the top left corner, in 'Select what to manager', select 'Another User ...'.
4. Search for the person. Click on 'OK'.
5. Click on 'Tell people you're on vacation'.
6. ...